The invention relates to a pencil sharpener and more specifically to a pencil sharpener for carpenters pencils. Some prior art pencil sharpener patents will now be discussed.
The Jones U.S. Pat. No. 240,520 is directed to a pencil sharpener. To sharpen the pencil, insert the end in the slot E in the case A and push it forward over the cutting-blade C, and, as it is forced forward it will raise the pressure spring D, which will let it move up the inclined bearing-surface B to the stop or end of incline, above the cutting-blade C. Then as the pencil is drawn back and down the incline bearing-surface, with the pressure spring D bearing down upon it and forcing the pencil against the cutting-blade C, it will cause the cutting blade to cut off a shaving, which will pass out of the slot F. The continuous movement of the pencil forward and backward, and at the same time turning it around in the fingers, so as to bring all of its surfaces to the cutting blade, will sharpen it to a point in the center on the same pitch as the pitch of the inclined bearing surface.
The Mead U.S. Pat. No. 716,732 is directed to a pencil sharpener having a housing and a cover with aligned apertures 2 and 5 in one of their ends. In the operation of the sharpener, the pencil is pushed inwardly through the coinciding openings 2 and 5 and between the inner recessed ends of the flanges 9 of the guide and also a suitable distance between and beyond the inner cutting edges 14 of the blades 13. The operator then reciprocates the pencil longitudinally to cut away the wood and taper the end of the lead. During such operation the end of the pencils being sharpened can be seen through the opening 6 and the cover. The shaving and lead particles may be discarded from the sharpener through the outlet opening 6.
The Davis U.S. Pat. No. 1,531,738 is directed to a pencil sharpener. It has a box with an aperture formed in its one end within which there is a cylindrical guideway passage 25. When the end 59 of pencil 60 is inserted through the guideway passage 25 of the sleeve 24, it will tend to push the finger 41 and the cutter blade 50 apart at their free forward portions and by rotating the pencil relatively to the device, the cutting edge 57 of the knife will pare the portion 59 and owing to the resilient pressure on the finger 41 and cutter 50 the paring will take place in the form of a taper.
The Rew U.S. Pat. No. 1,775,601 is directed to a pencil sharpener. It has blades 9 and 10 that are formed from resilient material and have their free ends terminating in beveled cutting edges 13 which are normally disposed in contacting engagement that are separated when a pencil is passed through the bore 6 as shown in FIG. 5 of the drawings. The strip 4 is adapted to limit the movement of the pencil in the sharpener, and when the pencil is withdrawn a cutting edge 13 cuts through the wood and the pencil lead giving it a sharpened end as illustrated in FIGS. 9 and 10 of the drawings.
The Herbold U.S. Pat. No. 2,982,253 is directed to a sharpener for carpenter pencils. In using the device a pencil is inserted in the open end of the body the desired amount and the pencil and the body are relatively reciprocated. Flexible blades will yield outwardly on the inward movement of the pencil and will sharpen the latter on the outward stroke of the pencil, the shavings falling out of the openings 14 and 16. The blade 17 will not merely cut the wood down to the lead of the pencil but the blades 15 will also sharpen the lead in a flat pointed marking edge.
The Jones U.S. Pat. No. 3,851,687 is directed to a pencil sharpener particularly adapted for use with carpenters' pencils and the like. When the pencil 20 is inserted into the channel 14, it moves the blades 22 out of the way causing them to pivot toward the wall 18 against the biasing force of a resilient biasing means disposed in the container. The biasing means comprises a compression spring 44 connected to each blade 22 adjacent the inner end of the surface 40 thereof and also appropriately connected to the wall 18.
The Gillson U.S. Pat. No. 6,256,892 is directed to a carpenter's pencil sharpener. To use, a carpenter's pencil is inserted into one of the bores 20 or 22. Razorblade 28 is pushed upwardly on the mass of the pencil and is resiliently held to said pencil by springs 32 while allowing the pencil to slide freely. When the pencil is withdrawn, cutting edge 30 engages and whittles the tip of the pencil as springs 32 keep edges 30 in firm contact with the pencil. The two bores 20 and 22 allow a user to sharpen both the long sides and the short sides of the oval profile of the pencil with one cutting edge. This patent expires in 2021. The structure of your device would not infringe any of the claims of this patent.